Bending Head, Especially for an Automatic Bending Machine

ABSTRACT

The invention relates to a bending head, especially for an automatic bending machine, containing a pair of bending rolls ( 1, 2 ) and a bending support ( 3 ), whereby below the first bending roll ( 1 ) is arranged transversely on the bending head a bending arm ( 20 ), which is positioned with its longitudinal axis perpendicularly to the longitudinal axis of the first bending roll ( 1 ), the bending arm ( 20 ) is mounted on the bending head with one of its ends rotatably about the longitudinal axis of the first bending roll ( 1 ) and is coupled to a drive, while at the other end of the bending arm ( 20 ) is mounted rotatably about its longitudinal axis the second bending roll ( 2 ), whose longitudinal axis is parallel to the longitudinal axis of the first bending roll ( 1 ). The second bending roll ( 2 ) is coupled to the first bending roll ( 1 ) with the aid of means of forced torque transmission, whereby both rolls ( 1, 2 ) are provided with mutually axially symmetrical lightweight sections (X) of their circumferences, the first bending roll ( 1 ) is coupled to a drive of its rotary motion with a controlled angle of rotation and the bending arm ( 20 ) is coupled to a drive of bidirectional bending, whereby the bending support ( 3 ) is formed by a bending support for bidirectional bending.

TECHNICAL FIELD

The invention relates to a bending head, especially for an automatic bending machine, containing a pair of bending rolls and a bending support, whereby below the first bending roll on the bending head is transversely arranged a bending arm, which is situated with its longitudinal axis perpendicularly to the longitudinal axis of the first bending roll, whereby the bending arm is mounted on the bending head with one of its ends rotatably about the longitudinal axis of the first bending roll and is coupled to a drive, whereas the second bending roll is mounted rotatably about its longitudinal axis at the other end of the bending arm, the longitudinal axis of the second bending roll being parallel to the longitudinal axis of the first bending roll.

BACKGROUND ART

A number of automatic bending machines containing a bending head with a bending pin, a bending arm and a bending support are well-known, for example, from the patent documents U.S. Pat. No. 6,009,737 and U.S. Pat. No. 5,495,740. The bending arm is along with the bending pin coupled to a bending drive for joint rotation of the bending arm and the bending pin about the longitudinal axis of the bending pin. The bending arm contains a bending plate, which is reversibly displaceable towards and away from the bending pin and which is coupled to the drive. The bending head further contains a bending support, which is provided with a support plate, which is reversibly displaceable with its drive to a position in front of the bending pin and the bending arm in which the bent material is situated during a bending operation. The drives of the individual components of the automatic bending machine, i.e. the drives of the bending arm and bending support, the drives of the positioning and gripping device of the bent material, as well as the bending drive, are coupled to a control mechanism of the automatic bending machine, which coordinates their operations, thus controlling the overall operation of the automatic bending machine.

CZ PV 2006-289 discloses a bending head for an automatic bending machine containing a longitudinal bed with a positioning and gripping device, whereby the bending head contains a bending support with an adjustable support plate, which is provided with a shape groove for the bent material and which is coupled to a drive coupleable to the control mechanism of the automatic bending machine. The support plate is mounted on a support pin, which is slidingly mounted in the body of the bending support, whereby it is coupled to an outlet member of a linear drive, which is coupled to the control mechanism of the automatic bending machine, the bending support being provided with a locking device of the bending plate.

CZ UV 24556 describes a bending device containing a longitudinal bed with a movable positioning and gripping device, which is aligned with a bending head containing a jointly rotatable bending pin and bending arm with an adjustable bending plate. The longitudinal bed is made up of longitudinal segments, whereby at one end of the longitudinal bed is selectably mounted a linear magnetic motor coupled to a positioning and gripping device or an electric servo motor with a motion belt coupled to the positioning and gripping device, whereas at the other end of the longitudinal bed is located a vertically and laterally adjustable bending head, whose bending arm is selectably situated on the right or left side of the bending head, whereby the bending plate on the bending arm is selectably composed of a bending stone or a bending roll or a bending roll with defined rolling away along the bent material during the bending operation.

A common disadvantage of the bending heads known so far from the background art is the fact that without substantial rearrangement they only allow to perform bends in one direction, i.e. by turning the bending roll either only to the right, or only to the left. If need arises to change the direction of bending, it is necessary either to use two separate bending heads with opposing rotation direction of the bending roll, which is demanding in economic terms and decreases the effective utilization of the two bending heads, or it is necessary to rearrange the bending head to enable the opposite direction of rotation of the bending roll, which is economically challenging, since during the rearrangement the bending machine is blocked and is out of operation, or it is necessary to turn the bent material, which places increased demands on handling devices and the space around the bending machine, as a number of bent products have a relatively large length. Another disadvantage of the background art is the fact that the feasibility of conducting two or more bends in immediate succession is limited, or it can only be done with a minimal length of a straight section between the bends.

The aim of the invention is to enable selectable and fast utilization of bends in both directions on a single device without having to rearrange it, while still maintaining productivity, accuracy, sufficient simplicity of the device and its long service life, and at the same time to allow individual bends to be arranged immediately one after another or only with a minimal spacing, i.e. minimal straight sections between each other.

Principle of the Invention

The goal of the invention is achieved by a bending head, especially for an automatic bending machine, whose principle consists in that the second bending roll is coupled to the first bending roll with the aid of means of forced torque transmission, whereby both rolls are provided with mutually axially symmetrical lightweight sections of its circumference, the first bending roll is coupled to a drive of its rotary motion with a controlled angle of rotation and the bending arm is coupled to a drive of bidirectional bending, the bending support being formed by a bending support for bidirectional bending.

The advantage of this arrangement is the fact that it is possible to carry out both “left” bends and “right” bends without having to rearrange the bending head and, at the same time, to conduct bends spaced with minimum distances between each other, i.e. bends with a minimum length of straight sections between each other, or even bends immediately following each other, i.e. bends without straight sections between each other.

DESCRIPTION OF DRAWINGS

The invention is schematically represented in the drawings, where FIG. 1 shows an overall view of a bending head, FIG. 2 shows a plan view of the bending head at the moment of the bending rolls being opened for inserting a bent tube and setting the head for bending to the left side, FIG. 3 shows a plan view of the bending head after closing the bending rolls for inserting a bent tube for bending to the left, FIG. 4 is a plan view of the bending head with an inserted bent tube and the bending rolls turned to the initial position for bending by 85° to the left, FIG. 5 is a plan view of the bending head after performing a bend by 85° to the left (FIG. 4) with the indicated mutual position of mutually corresponding lightweight sections of the circumference of both bending rolls, FIG. 6 is a plan view of the bending head at the moment of rearrangement of the bending rolls for a bend to the right and with opened bending rolls for inserting the bent tube, FIG. 7 is a plan view of the bending head from FIG. 6 for closing the bending rolls after inserting the bent tube for a bend to the right, FIG. 8 shows the turning of the bending rolls for bending to the right by 85° with a minimal straight section between the preceding and following bends and FIG. 9 shows carrying out a bend by 85° to the right with a minimal straight section between the preceding and following bends and with the final mutual position of the bending rolls.

SPECIFIC DESCRIPTION

The invention will become apparent from the description of an example of embodiment of a bending head for an automatic bending machine which is provided with a gripping device and, where appropriate, also with a positioning device of the bent material 0, whereby the individual components of the machine, including the bending head, are provided with drives and are connected to a control mechanism of the bending machine, so that bends can be formed at a desired location of the bent material 0, in a desired direction and at a desired angle. In addition, the bending head according to the invention is designed for carrying out bends in both directions, i.e. both to the right and to the left, and, at the same time, it is designed for performing bends immediately one after another or only with a minimal length of straight sections between the individual bends.

Generally, the bending head is situated at the end of the machine and contains the first bending roll 1, which is mounted rotatably about its longitudinal axis in the frame of the bending head and is connected to a source of rotary motion. The first bending roll 1 is along its circumference provided with a shape groove 10 for the bent material 0, such as a tube, a pipe, a bar etc.

Below the first bending roll 1 on the bending head is transversely arranged a bending arm 20, which is situated with its longitudinal axis perpendicularly to the longitudinal axis of the first bending roll 1, whereby the bending arm 20 is mounted on the bending head with one of its ends rotatably about the longitudinal axis of the first bending roll 1.

The second bending roll 2 is mounted rotatably about its longitudinal axis at the other end of the bending arm 20, whereby the longitudinal axis of the second bending roll 2 is parallel to the longitudinal axis of the first bending roll 1 and at the same time it is perpendicular to the longitudinal axis of the bending arm 20.

As a result, both bending rolls 1, 2 are rotatably mounted on the bending arm 20 about their parallel longitudinal axes, whereby the second bending roll 2, due to being mounted on the bending arm 20, is able to revolve around the first bending roll 1. The bending arm 20 is coupled to a drive of its bidirectional rotary motion, e.g., with a rotary motor 8, i.e. the drive of bidirectional bending.

As is apparent from the above description, the bending arm 20 is disposed transversely with its longitudinal axis to both rolls 1, 2 and is rotatable about the longitudinal axis of the first bending roll 1, whereby the second bending roll 2 moves together with the bending arm 20.

The first bending roll 1 is with the aid of the means of forced torque transmission rotatably coupled to the second bending roll 2, and, consequently, the second bending roll 2 during the rotation of the bending arm 20 about the longitudinal axis of the first bending roll 1 continuously rolls away with its lateral surface substantially over the lateral surface of the first bending roll 1 or, if the two rolls 1, 2 do not directly abut each other with their lateral surfaces, it rolls away in the vicinity of the lateral surface of the first bending roll 1.

So as to facilitate insertion and removal of the bent material 0 into and from the bending shape groove in each of the bending rolls 1, 2 and, above all, so as to minimize or completely eliminate straight sections of the bent material 0 between the individual bends, so that the bends would directly follow each other, both bending rolls 1, 2 are provided with mutually corresponding, i.e. mutually functionally coordinated lightweight sections X of their circumference, the lightweight section X having a shape of a cut-off circular segment in a plan view, as shown in FIGS. 2 to 7.

Mutual coordination of the function of the lightweight sections X of the circumference of each of the bending rolls 1, 2 is achieved by the above mentioned means of forced torque transmission between the two bending rolls 2, which thus rotate jointly counter-directionally and their lightweight sections X of the circumference are always located mutually axially symmetrically to the axis situated in a common tangent line to both bending rolls 1, 2. By joint forced mutually counter-directional motion of the two bending rolls 1, 2 it is possible not only to restrain or prevent possible skidding of the bending rolls 1, 2, particularly of the second bending roll 2, over the surface of the bent material 0, such as tubes, pipes, and to prevent possible damage to the surface of the bent material 0, but mainly it is possible to achieve synchronization of the movement and position of the lightweight sections X of the circumference of the two rolls 1, 2 in accordance with the principles of axial symmetry, as will be described in greater detail further on in the section dealing with the function of the bending head.

In the illustrated embodiment, the means of forced torque transmission of both rolls 1, 2 are formed by a pair of toothed wheels 4 which are in mutual engagement, wherein one toothed wheel 4 is mounted below the first bending roll 1 and the other toothed wheel is mounted below the second bending roll 2 and each of the toothed wheels 4 is secured against being turned relative to the bending roll 1, 2 below which it is arranged, e.g., it is pinned to this roll or otherwise suitably connected. For the purpose of synchronized rotation of both rolls 1, 2 apart from performing bends which is used both during setting the mutual mirror position of lightweight sections X of the lateral circumference of each of the rolls 1, 2 when need arises to carry out a bend by a defined angle and with a minimal length of straight sections between the bends both when inserting and removing the bent material 0 into and from the bending shape groove in each of the bending rolls 1, 2 the first bending roll 1 is coupled to the drive of its rotary motion, e.g., to a rotary motor 7, so that the rotary motion of the first bending roll 1 is mirror transmitted into the rotary motion of the second bending roll 2. The drive of the first bending roll 1 is provided with monitoring the position of the shaft, thus enabling the turning of the first bending roll 1, and, consequently, also of the second bending roll 2, into the accurately required axially symmetrical mutual position of the lightweight sections X of the circumference of both rolls 1, 2.

The pair of bending rolls 1, 2 is further aligned with a bending support 3 for bidirectional bending, which is used to absorb reaction forces occurring during the bending of the bent material 0 between the bending rolls 1, 2 and their mutual movement both to the left and to the right due to the second bending roll 2 being mounted on the transverse bending arm 20. In the illustrated example of embodiment, the bending support 3 is composed of a flat body, which is swingingly mounted in the frame of the bending head, e.g., it is mounted at one end of a pivot 30, which is rotatably mounted in the frame of the bending head, whereby at its other end it is coupled to the drive of its rotary motion, e.g., at its other end it is provided with a control lever 31, to which is connected a movable part of a linear drive 6, whose fixed part is mounted on the frame of the bending head.

The bending head operates such that when it is necessary to perform a bend to the left, the bending arm 20 turns so that the second bending roll 2 is situated (in a plan view) on the right of the first bending roll 1, see FIGS. 2 to 4, whereupon both rolls 1, 2 turn with their lightweight sections X of the lateral circumference against each other (by turning the first bending roll 1 about its longitudinal axis, whereby this rotary motion is transmitted via the toothed wheels 4 to the second bending roll 2). Subsequently, the bent material 0 is inserted into the gap formed by the lightweight sections X in the lateral walls of the rolls 1, 2 and both rolls 1, 2 reversibly turn about their longitudinal axes, by which means the lightweight sections X in the lateral walls of the rolls 1, 2 tilt away from each other into a position which does not hinder subsequent bending, and so the bent material 0 is closed between the bending rolls 1, 2 to perform the bending operation. When inserting and removing the bent material 0 into and from the rolls 1, 2, the bending support 3 is tilted down not to hamper the handling operations in the vicinity of the rolls 1, 2. The bending operation itself is carried out by turning the bending arm 20 to the left about the longitudinal axis of the first bending roll 1 to reach the desired angle, see FIG. 5, and backwards. After the bending arm 20 returns back, both rolls 1, 2 again turn against each other about their longitudinal axes with their lightweight sections X in the lateral walls of the rolls 1, 2, thereby releasing the bent material 0 for further handling and for setting up for another bend.

When it is necessary to perform a bend to the right, the bending arm 20 turns in such a manner that the second bending roll 2 is situated (in a plan view) on the left side of the first bending roll 1, see FIGS. 6 and 7, whereupon both rolls 1, 2 turn with their lightweight sections X of the lateral circumference against each other (by turning the first bending roll 1 about its longitudinal axis) and this rotary motion is transmitted via the toothed wheels 4 to the second bending roll 2. Subsequently, the bent material 0 is inserted into the gap formed by the lightweight sections X in the lateral walls of the rolls 1, 2 and both rolls 1, 2 turn reversibly about their longitudinal axes, by which means the lightweight sections

X in the lateral walls of the rolls 1, 2 tilt away from each other to a position which does not hamper the subsequent bending, and so the bent material 0 is closed between the bending rolls 1, 2 for bending. When inserting or removing the bent material 0 into and from the rolls 1, 2 the bending support 3 is tilted down to allow unrestricted handling operations in the vicinity of the rolls 1, 2. The bending operation itself is carried out by turning the bending arm 20 to the right about the longitudinal axis of the first bending roll 1 to reach the desired angle and backwards. After the bending arm 20 returns back, both rolls 1, 2 again turn about their longitudinal axes of their lightweight sections X in the lateral walls of the rolls 1, 2 against each other, thereby releasing the bent material 0 for further handling operations and for setting up for another bend.

If a change in parameters of bending is required, e.g., a change in the bend radius, or when the bent material 0 has a different size or shape of the inter-section, the bending rolls 1, 2 are replaced, and, in case of need, also the toothed wheels 4 are replaced, the bending support 3 and, as the case may be, the individual parts of the bending head 3 are adjusted to achieve the desired final and initial positions, whereby the program according to which the bending head is controlled, also depending on other parts of the bending machine, is modified or a new program is used etc.

During a bending operation with the requirement for a minimal or zero straight section between the individual bends, it is necessary to make sure that the circumference of none of the bending rolls 1, 2 intersects the position of the bent material 0 from the preceding bend, because otherwise it would not be possible to perform the bend. Therefore, prior to carrying out the following bend with a small or no spacing from the preceding bend, it is necessary for both rolls 1, 2, to turn with their lightweight sections X into such an initial position that after performing a bend to reach the desired angle (the rolls 1, 2 mutually roll away from each other during the bending operation) both rolls 1, 2 end up with their lightweight sections X in a common line, as shown in FIG. 5, which illustrates the final mutual position of both rolls 1, 2 and the lightweight sections X of their circumference when turning by an angle of 85°, whereby the initial mutual position of both rolls 1, 2, and the lightweight sections X of their circumferences for this bend is shown in FIG. 4. 

1. A bending head, especially for an automatic bending machine, containing a pair of bending rolls (1, 2) and a bending support (3), whereby below the first bending roll (1) is transversely arranged on the bending head a bending arm (20), which is situated with its longitudinal axis perpendicularly to the longitudinal axis of the first bending roll (1), the bending arm (20) is mounted on the bending head with one of its ends rotatably about the longitudinal axis of the first bending roll (1) and is coupled to a drive, while at the other end of the bending arm (20) is mounted rotatably about its longitudinal axis the second bending roll (2), whose longitudinal axis is parallel to the longitudinal axis of the first bending roll (1), characterized by that the second bending roll (2) is with the aid of means of forced torque transmission coupled to the first bending roll (1), whereby both rolls (1, 2) are provided with mutually axially symmetrical lightweight sections (X) of its circumference, the first bending roll (1) is coupled to a drive of its rotary motion with a controlled angle of rotation and the bending arm (20) is coupled to a drive of bidirectional bending, whereby the bending support (3) is composed of a bending support for bidirectional bending. 2-4. (canceled) 